The word about 'overdiagnosis' is a regular feature in medical journals, stories are found at least weekly in major newspapers, and patients are starting to question whether cancer screening tests are really right for them.

Victory!

Ok, no no, we are a long way from finding the right balance of too much and too little medicine. But now that we accept that 'too much medicine' is a real thing, we need to figure out just how big the problem is.

Overdiagnosis, according to Ubel, occurs when we detect things that would never have caused a problem for the patient. He gives the example of a tiny breast cancer that would never have been noticeable in an elderly woman (who would undoubtedly die of something else first). When trying to change the culture to encourage people to stay away from screening tests that will lead to overdiagnosis, we are up against several challenges. One of those is the fact that early diagnosis can sometimes make it seem like we live longer if we detect the cancer earlier, though finding it early doesn't improve or save our life (lead-time bias, which is explained in the article).

Ultimately, in order to quantify the prevalence of overdiagnosis, we will need population-level data after a screening program has been introduced, and the data will need to be measured for long enough that any of the lead time bias effect will have passed.